The present invention relates generally to fastener driving tools, and particularly to such tools being powered electrically, by compressed gas, combustion or powder.
Combustion-powered tools are known in the art, are also referred to as combustion nailers, and one type of such tools, also known as IMPULSE® brand tools for use in driving fasteners into workpieces, is described in commonly assigned patents to Nikolich U.S. Pat. Re. No. 32,452, and U.S. Pat. Nos. 4,522,162; 4,483,473; 4,483,474; 4,403,722; 5,197,646; 5,263,439 and 6,145,724, all of which are incorporated by reference herein. Similar combustion-powered nail and staple driving tools are available commercially from ITW-Paslode of Vernon Hills, Ill. under the IMPULSE® and PASLODE® brands.
Combustion nailers incorporate a tool housing enclosing a small internal combustion engine. The engine is powered by a canister of pressurized fuel gas, also called a fuel cell. A battery-powered electronic power distribution unit produces a spark for ignition, and a fan located in a combustion chamber provides for both an efficient combustion within the chamber, while facilitating processes ancillary to the combustion operation of the device. Such ancillary processes include: inserting the fuel into the combustion chamber; mixing the fuel and air within the chamber; and removing, or scavenging, combustion by-products. The engine includes a reciprocating piston with an elongated, rigid driver blade disposed within a single cylinder body.
Upon the pulling of a trigger switch, which causes the spark to ignite a charge of gas in the combustion chamber of the engine, the combined piston and driver blade is forced downward to impact a positioned fastener and drive it into the workpiece. The piston then returns to its original, or pre-firing position, through differential gas pressures within the cylinder. Fasteners are fed magazine-style into the nosepiece, where they are held in a properly positioned orientation for receiving the impact of the driver blade.
Other fastener driving tools operate similarly in that a reciprocating driver blade drives fasteners fed to a nosepiece by a biased magazine. The power source varies, with pneumatic, electric and powder operated tools being well known in the art.
Combustion nailers and other types of powered fastener driving tools are used in construction framing, where building panels such as plywood, wallboard, roof sheathing or other construction panels are secured to framing studs with fasteners, typically nails. A common problem for installers is making sure that the fastener is driven into a stud to effectively secure the panel in place. Fasteners not engaging the stud represent a wasted effort, as well as wasted materials, and wasted fuel in the case of the combustion tool.
Many installers employ separate stud finders to facilitate location of the studs, which entails additional effort and inconvenience in carrying and maintaining an extra battery-powered device. Also, the installer cannot always easily see the stud finder's readout while working, and the use of these devices slows production, so professional installers do not typically use separate stud finders. Alternatively, other installers measure the spacing of the studs from a corner or panel edge, often using a chalk line, since studs are conventionally built on 16 inch centers or some other standard depending on the geographic location. However, the latter method is not foolproof, and studs are still missed by driven fasteners.
Also, conventional fastener driving tools are available with built in stud finders. Such devices locate the stud, but do not indicate whether the fastener was properly driven into both the panel and the supporting stud, or improperly, only into the panel. As such, the available techniques for accurately driving fasteners are not consistently accurate, and the problem of misdirected fasteners persists in the context of framing construction.